scholarly journals Kinetic study on the removal of heavy metals by Cajanus Cajan husk

2019 ◽  
pp. 206-229
Author(s):  
Mallappa A. Mallappa A. Devania, Mallappa A. Devania ◽  
Basudeb Munshi

The removal of heavy metals from wastewater has become crucial to meet safe discharge standards. Development of more economic process has been strived owing to high cost of adsorbents. Thus, biosorption process has become the area of interest to researchers and engineers. The present study has carried out the transient removal of heavy metals from wastewater by both physically treated and chemically modified Cajanus cajan (Pigeon pea) husk (CCH) as novel biosorbents. Work includes five different models such as first order, second order, nth order, first order reversible and second order reversible under the heading of prediction of transient concentration of metal in the solution are used, and under the heading of prediction of transient metal uptake capacity; fractional power, pseudo first order, pseudo second order, second order reversible, Elovich, intra-particle diffusion and film diffusion models are used to analyse the kinetic data. For a metal at any particular initial concentration the best kinetic model with the least RMSE is identified. Pictorial comparison between experimental and pseudo second order and pseudo first order model predictive data of Cd(II) and Cu(II) transient biosorption, respectively onto CCH are illustrated. The trend of the results shows a successful prediction capability of all the kinetic models used in the present work. According to RMSE data, it can be concluded that the best kinetic models are pseudo second order for Cd(II) and pseudo first order for Cu(II). It has been found that the required equilibrium time is always less for the chemically activated than the physically activated sorbent. At 100 mg/L initial metal concentration, pseudo-first-order model has been identified as the best kinetic model for the transient Cu(II) and the best kinetic model for fitting the transient sorption of Cd(II) on CCH is pseudo-second-order. At initial metal concentration of 150 mg/L, initial biosorption rate of 9.7038 for Cd(II) on CCH(N) is greater than 1.4553 for Cu(II) on CCH(N). These indicate that Cd(II) undergoes faster adsorption rate than Cu(II) onto CCH.

2011 ◽  
Vol 356-360 ◽  
pp. 1289-1292
Author(s):  
Dan Fu ◽  
Yi He Zhang ◽  
He Li Wang ◽  
Feng Zhu Lv

In this paper, the adsorption properties of TNT on Rice husk active carbon (RHAC) were investigated. The effects of contact time was examined. Kinetic data obtained at different concentrations were conducted using Lagergren’s pseudo first-order, pseudo second-order and diffusion models. The regression results showed that the adsorption kinetics was more accurately represented by pseudo second-order model. The study indicates that there is significant potential for RHAC as an adsorbent material for TNT removal from wastewater.


Author(s):  
C. Obi ◽  
N. C. Ngobiri ◽  
L. C. Agbaka ◽  
M. U. Ibezim-Ezeani

The study focused on the investigation of the effectiveness of the pericarp of monkey kola (Cola lepidota) biomass (CLPB) in the removal of toluene from aqueous system. X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and phytochemical screening methods were used for characterizing the biosorbent. The effects of contact time, pH, and concentration on biosorption process were studied. The phytochemical screening showed the presence of alkaloids, flavonoids, tannins, carbohydrate, saponins and steroids. Carboxylic, alkene and alcohol groups were found to be the principal functional groups. The highest percentage removal was 99.63% at toluene initial concentration of 40 mg/L and 98.30% at pH 8. The contact time 30 minutes gave better removal efficiency of 99.89%. Among the biosorption isotherm models tested (Langmuir, Freundlich, Dubinin Radushkevich and Temkin, respectively), the Langmuir model equation gave a better fit of the equilibrium data with a correlation coefficient (R2) of 0.99. The equilibrium data was tested with pseudo-first order and pseudo-second order models and pseudo-second order model (R² = 0.99) fitted more than the pseudo-first order model (R² = 0.85). This study has revealed that Cola lepidota is a potential biosorbent for the removal of toluene from aqueous medium under the operating conditions of contact time of 30 minutes, pH of 8 and initial concentration of 40 mg/g.


2017 ◽  
Vol 79 (7) ◽  
Author(s):  
Abdulganiyu Umar ◽  
Mohd Marsin Sanagi ◽  
Ahmedy Abu Naim ◽  
Wan Nazihah Wan Ibrahim ◽  
Aemi Syazwani Abdul Keyon ◽  
...  

In this work, polystyrene modified-chitin was evaluated for the first time as adsorbent for the removal of Orange G from aqueous solutions. Its absorption capacity was compared to that of chitin. BET and FESEM results showed that the polystyrene-modified chitin has higher surface area (12.47 m2/g) compared to chitin (4.92 m²/g). Batch adsorption experiments on the removal of Orange G from aqueous solutions were conducted. The results showed that the polystyrene-modified chitin has improved adsorption capacity compared to chitin. The maximum adsorption of orange G by chitin occurred at pH 2, while that of the polystyrene-modified chitin occurred at pH 6. At an initial concentration of 20 mg/L, the percentages of dye removal were 65.16% and 81.20% for raw chitin (RCH) and polystyrene-modified chitin (MCH), respectively. Kinetics studies for the adsorbents were conducted using pseudo-first-order and pseudo-second-order models. The pseudo-first-order model gives poor fittings for both adsorbents, with low coefficients of determination (R2). The pseudo-second-order model fits the experimental data well, with R2 close to unity. Langmuir and Freundlich models were used to interpret the adsorption isotherms. It was found that Langmuir isotherm conformed better than Freundlich model in the adsorption of selected dye on chitin and the polystyrene-modified chitin, with R2 nearly unity.


2013 ◽  
Vol 726-731 ◽  
pp. 2191-2197 ◽  
Author(s):  
Su Yun He ◽  
Cai Yun Han ◽  
Su Fang He ◽  
Hua Wang ◽  
Chun Xia Liu ◽  
...  

This research presented the kinetic performance of arsenic absorption by mesostructure SBA-15 functionalized with Al2O3. The SBA-15 was previously synthesised and subsequently functionalized via impregnation of alumina oxides. The absorption of arsenic(V) was studied as a function of absorbent dosage and contact time. The experimental data were fitted to kinetic pseudo-first order, pseudo-second order and the intra-particle diffusion model. The pseudo-second order model presented the best correlation with the experimental data. Both surface absorption and intra-particle diffusion were acting during arsenic uptake, except for absorbent dosage of 0.1g, which was mainly controlled by the intra-particle diffusion.


Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5519
Author(s):  
Hector R. Guzmán-Carrillo ◽  
Alejandro Manzano-Ramírez ◽  
Ines Garcia Lodeiro ◽  
Ana Fernández-Jiménez

This paper reports an Alkali-Activated Materials (AAM) using two different precursors, metakaolin and a metallurgical slag with photocatalytic zinc oxide nanoparticles, as novel photocatalytic composites. The photodegradation performance of the composites using methylene blue (MB) dye as a wastewater model was investigated by ultraviolet radiations (UV-vis) spectroscopy. Adsorption in dark conditions and photodegradation under UV irradiation are the mechanisms for removing MB dye. The pseudo-first-order kinetic and pseudo-second-order kinetic models were employed, and the experimental data agreed with the pseudo-second-order model in both cases with UV and without UV irradiations. As new photocatalytic materials, these composites offer an alternative for environmental applications.


2010 ◽  
Vol 7 (s1) ◽  
pp. S511-S519 ◽  
Author(s):  
S. Senthilkumaar ◽  
S. K. Krishna ◽  
P. Kalaamanic ◽  
C. V. Subburamaan ◽  
N. Ganapathy Subramaniam ◽  
...  

Chemically activated “Waste” Jute Fiber carbon has been effectively used for the removal of five organophosphorous pesticides (malathion, monocrotophos, methylparathion, phosphamidon and dimethoate) from aqueous solutions. The prepared activated jute fiber carbon was characterized by using Elemental analyzer and proximate analysis methods. The adsorption equilibrium was examined at 28ºC. Three different kinetic models, the pseudo first order, pseudo second order and Elovich kinetic models were selected to analyses the adsorption process. To compare the fitness of pseudo first order and pseudo second order, sum of the squares of the errors and correlation coefficient, r2values were calculated. The Elovich model was used to confirm the chemisorptions.


2013 ◽  
Vol 781-784 ◽  
pp. 2296-2300
Author(s):  
Jian Qiu Chen ◽  
Zhi Liang Wang ◽  
Guo Ping Li ◽  
Rui Xin Guo ◽  
Yu Zhu Hu

Sorption of Acetazolamide was found to be impacted by clay content and soil solution pH, with higher Kd values for soils with higher clay content and higher Kd values as the pH increased. Sorption data on soils were well fitted with Freundlich model (R2> 0.98). The kinetics of adsorption of Acetazolamide has been discussed using four kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the Elovich equation, the intraparticle diffusion model. The pseudo-first-order model and the pseudo-second-order model were both used to describe the kinetics data, and the pseudo-second-order model could describe the sorption behavior of Acetazolamide well.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Javier Paul Montalvo Andia ◽  
Lidia Yokoyama ◽  
Luiz Alberto Cesar Teixeira

In the present work, the equilibrium, thermodynamics, and kinetics of boron removal from aqueous solutions by the adsorption on commercial magnesium oxide powder were studied in a batch reactor. The adsorption efficiency of boron removal increases with temperature from 25°C to 50°C. The experimental results were fitted to the Langmuir, Freundlich, and Dubinin–Radushkevich (DR) adsorption isotherm models. The Freundlich model provided the best fitting, and the maximum monolayer adsorption capacity of MgO was 36.11 mg·g−1. In addition, experimental kinetic data interpretations were attempted for the pseudo-first-order kinetic model and pseudo-second-order kinetic model. The results show that the pseudo-second-order kinetic model provides the best fit. Such result suggests that the adsorption process seems to occur in two stages due to the two straight slopes obtained through the application of the pseudo-first-order kinetic model, which is confirmed by the adjustment of the results to the pseudo-second-order model. The calculated activation energy (Ea) was 45.5 kJ·mol−1, and the values calculated for ∆G°, ∆H°, and ∆S° were −4.16 kJ·mol−1, 21.7 kJ·mol−1, and 87.3 kJ·mol−1, respectively. These values confirm the spontaneous and endothermic nature of the adsorption process and indicated that the disorder increased at the solid-liquid interface. The results indicate that the controlling step of boron adsorption process on MgO is of a physical nature.


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